Safety device for ships&#39; propeller shafts



March 20, 1945. H, E, c, WALPQLE 2,372,036

SAFETY DEVICE FOR SHIPS PROPELLER SHAFTS Filed may v. 194s 2Sheets-Sheet 1 MalCh 20, 1945- 'H. E. c. wALPoLE 2,372,036

SAFETY DEVICE FOR SHIPS PROPELLER SHAFTS Fed May '7. 1943 2 Sheets-Sheet2 Patented Mar. 20, 1945 faticose i SAFETY DEVIC Foa sHiPsPRoPELLEnsHAF'rs f y lslorace Edward Christopher Walpole,v Epsom, England i'Application May 7,1943,;serialNp.486,093l Irl-Great Britain May 27, 1942y f 6 Claims.

This invention relates to ships propeller shafts and has for its objectto provide a new or improved safety device to prevent the entry of waterinto a ship, boat or the like should the propeller shaft ybreak and slipout through the bearing in the stern of the hull, leaving space for theinrush of water.

According to the present inventionI provide a collar or flange fixed toor integral with the propeller shaft near to its bearing in the stern ofthe hull and I enclose the ycollar or iiange in a casing extendingaround the shaft rearwardly up to the front end of the propeller shaftbearing in the hull and forwardly beyond thesaid collar or flangewhereby if the shaft breaks rearwardly of the collar or flange and thepropeller and broken 01T portion of the shaft leave the ,ship theinrushing water is checked by the cas-r the shaft breaks.

ing after flooding it whilst if forwardly of the collar or flange thepropeller and broken olf portion carrying the collar or flan-ge moverearwardly until the rear face of the saidv collar or flange makessealing contact with the rear wall of the surrounding casing.

One embodiment of the invention is illustrated in the accompanyingdrawings in which:

Figure 1 is a longitudinal sectional elevation and Figure 2 is a planview of a portion of a propeller shaft in combination with the collar orflange and the enclosing casing according to the invention. Figure 3 isan end view of the shaft in section and the exterior of the casing inelevation. Figure 4 i's a cross sectional View on the line 4--4 ofFigure l.

Figure 5 is a fragmentary sectional view of a modication'in which thepropeller shaft and the flange thereon are integral.

The collar or flange a is shown clamped onto the propeller shaft b andycompletely enclosed -by the casing c of suitable shape or design. Thecasing c is mounted around the shaft extending through the stern A andbearing A of the hull, with the rear end d of the casing close up towhere the propeller shaft would Ibecome bare at Ve inside the hull so asto make a watertight 'joint there.

The front end f of the casing is connected in a watertight lmanner tothe next bearing (not shown) or is made watertight around the propellershaft at y as hereinafter described. Between the two ends f and d of thecasing it is considerably larger in diameterso as to allow space for thecollar or flan-gea to revolve inside with a good clearance as shown ati. The collar or flange a can be made in one, two,

or more parts and be secured to the shaft by any suitable means such asbolts and nuts as shown at i. Alternatively the said collar or flangecan "be made part of the propeller shaft b, las shown at a' in Figure 5,by being turned on the said shaft during manufacture, and can be anysuitable shape or design. An inspection plate or cover k can be fixed atthe top of the casing as shown or in any other suitable position, andcan be large enough to permit of attaching or removing or otherwiseattending to the collar or flange from inside the hull.

The said collar or flange aihas a disc shaped v' portion presenting anannular surface Z facing a similar raised surface m on the inside of therear end wall of the casing; Should the propeller shaft break at anyplace [between its collar or flange a and the engines or driving force,the propeller shaft would slip out only as far as the collar or flangewould allow by making contact between the surfaces l and m. The surfacel would strike the surface m, thus preventing the propeller shaft fromvpassing out of the bearing at the stern of theship. Shouldl thepropeller shaft break or become detached anywhere along it between thepoints n and o, the shaft would sli-p out, thus allowing the entry ofwater but only into the casing c as far as p, the remaining section ofthe propeller shaft b still being rin position.

The casing from p to s can have a small clearance with respect to theshaft, the diameter of the bore being slightly larger than the diameterof the shaft, and so give no resistance to the rotation of the shaft,yet at the same time preventing appreciable flow of water. This spacecan also be filled with grease or any other suitable substance toprevent the trickle ofwater' through .the clearance space, the greasebeing retained by small end collars t and u. A grease cap u is fixed forthe purpose of adding grease. Should the casing be extended beyond f'byattachinent to the next bearing of the shaft, the collar t nfeed not beused and the clearance around the shaft can be of appreciably largerldiameter than the outside diameter o f the shaft so as to ensureabsence of contactv and avoid resistance to rotation of the shaft.

What I claim ist 1. The combination with a ships propeller shaft and itsbearing in the stern ofthe ships hull of a collar on the said vshaftnear to the ysaid bearing and inside the stern of the hull and a casingenclosingr the said collar and extending around the shaft rearwardly upto the front end of the propeller shaft bearing in the hull andforwardly beyond the said collar or flange, and means for forming awater seal as between the internal surface of said casing and the rearface of said collar, whereby if the shaft breaks rearwardly of thecollar or flange and the propeller and broken oi portion of the shaftleave the ship the inru'shi'ng` iwateris' checked licy `the casing afterflooding it whilst' if the shaftbreaks` for wardly of the collar or angethe propellerand broken off portion carrying the collar or flange'A moverearwardly until the rea-r rface of, the said collar or ange makessealing contact witli the" rear wall of the surrounding casing.

2. The combination accordngft'd elainr E lili-`-z which the collar isintegral with the prolnllelv shaft.

3. The combination according toV claim'- l' in,

which the collar is in sections and attached to the propeller shaft.

4. The combination according to claim 1, including a disc portion withannular sealing surface on the collar and an opposing sealing surface onthe interior of the rear wall of the casing. 5. The `combinationaccording to claim 1, in which there 'is apprecialcIear-amce: spacebetween the propeller shaft and the surrounding surface of the front endwall of the casing, and means at each end of the annular clearance spacewhereby grease may be retained insaid space.

6. The combination according to claim 1, lin which thefcasing comprisesa body portion and arremovable cover plate.

HORACE EDWARD A CHRISTOPHER WALPOLE.

